Hello and Water Pump Question

[timandsam]

Hi All! About 6 months ago my wife purchased a super clean alpine white 2010 X5 3.0i. This is our first BMW and we both really enjoy the car! I have already done a trans fluid/pan change, front and rear diff fluid, transfer case fluid, drive belt, belt tensioner, and the engine partitions. It currently has 99K on it.

Now I am seeming to have an issue I am hoping you guys can give some advise on...

On Sunday night, my wife started it up (the engine was completely cold) and there was a LOUD high pitched whining noise coming from under the hood. I had her rev the engine but it was apparent that the noise did not fluctuate with engine speed. I had her shut the car off and restart it. The noise want away and we drove home without issue (about an hour and a half).

On Monday, I took the X5 to work. At lunch, I sat in the car and let it idle for about an hour while I ate. When I shut it off, i got out and noticed a coolant smell. I looked under and saw no signs of leaking and went inside thinking i would check it out later. When I came back outside about a half hour later there was coolant all over the ground. Upon inspection, it appears as though the leak is coming from the bottom of the expansion tank.

We got the car towed home where it currently sits. A high temp light never came on, but the low coolant level warning did come on when we drove it on to the tow truck.

So, my question to you guys is, are the noise and the blown out expansion tank related? Are these both symptoms of a bad water pump?

I would hate to just replace the surge tank just to have the car overheat 5 miles up the road.

What do you guys think?

Thanks in advance!!!
-Tim

[B4_685]

Hi Tim,

I had both fail together (E70 N63) - the pump was making wierd clicking and humming noises and shortly thereafter the coolant tank failed(presumably coincidentally as the pump was still ok but bearings worn to the point the impeller was touching the internal seal of the impeller housing). Low coolant levels caused by a leak can also manifest in strange noises from the electric pumps cavitating or running without sufficient fluid in the lines (as was the case when my coolant system wasn’t quite air free after running the bleeding process). Mine ran low on fluid so I believe the tank experienced an overpressure leading to rupture as the steam pressure exceeded the plastic tanks design.


2012 E70 5.0iX

[ard]

^great post

[timandsam]

Thanks. My car was not low on coolant when this happened, but it is now that it puked up what looks to be about 1-2 quarts from the surge tank.

I performed thed self bleed procedure and took a video. Does this sound normal to you guys? Sounds pretty bad to me.

https://youtu.be/zBv8VkxU0a0

[smassey321]

Originally Posted by timandsam

Thanks. My car was not low on coolant when this happened, but it is now that it puked up what looks to be about 1-2 quarts from the surge tank.

I performed thed self bleed procedure and took a video. Does this sound normal to you guys? Sounds pretty bad to me.

https://youtu.be/zBv8VkxU0a0

That noise is not normal. All you should hear is bubbles in the hoses. Bleed procedure should be done with the cap on but I doubt that will change that sound.

[B4_685]

Sounds like a mini diesel engine hiding under there - I’d probably add a bit more coolant when you are bleeding - any other leaks in the system? The N63 cooling circuit for the turbo lines have 2 bleed screws on the top of the engine that I had to crack open with the engine running in order to bleed the auxilary cooling circuit as the self bleed pump couldn’t get coolant all the way to the top of the engine (maybe its a bit tired after 100000km). Until I did that I had all sorts of funny loud Spinning impeller noises as the pump was surging as it was loaded/unloaded with fluid.


2012 E70 5.0iX

[timandsam]

I haven't topped it off since the expansion tank split. I am trying to figure out if I need to order just the expansion tank and coolant or if i need a water pump too right away. The car is definitely low on coolant, but it really only lost what was in the expansion tank. Maybe 2 quarts?

It's too cold here in PA to just put straight water in to test it, and I don't really want to put anything other than BMW coolant in it either...

[Vanguard]

I would replace both the expansion tank and the water pump now. Overheating the engine is likely get very unpleasant and expensive really quick.

[Eric Giles]

I echo the suggestions already made...replace the expansion tank and water pump...but also the thermostat while you have it all apart.

Since your new to BMW's I would also offer a suggestion...never let a BMW sit and idle that long unless absolutely necessary. Some may disagree with me, but BMW cooling systems get so fragile with age, that I just recommend that scenario...even with replacing the parts mentioned.

[crystalworks]

Re-echoing others. One of the first things I do with any used BMW purchase is the entire (almost) cooling system. Water pump, thermostat, expansion tank, and hoses. Those parts are all on borrowed time over ~100k miles. I'll leave secondary pumps, radiators (except on m62 powered BMWs), and heater control valves if they show no signs of imminent failure.

Also don't like the idea of idling that long. Not for any real reason... Just couldn't see doing that.